Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Question for CARDOC about Heat Soak

I read in an earlier post when I was searching for "heatshield" info that you were working on an alternative to a heat shield that wouldn't be sheet metal, etc., and could be "purchased locally for about .50"

You said something about experimenting and would let us all know the results--I was just wondering what the results were, if you have any results, and what you may be talking about?

Thanks!

The fix that has worked well for those of us over here in Ohio and a few other places..(lol) is installing a 5.6K ohn resistor inline with the air temp sensor. It makes the computer see air temps 20 degrees lower than actual.. Which enrichens the fuel mixture and advances the ignition timing.. Providing greater performance... and cutting down on the air temp gets rid of the lean condition with KKM's installed .. The "Heatsoak" is when the engine's heat is absorbed into the intake tracts and induction system.. The IAT then responds to the computer with an astronomically high temp reading that thoroughly leans the mixture out which hurts start up performance and drivability until it cools.

The above resistor can be found at Radio Shack for about $.50 for a 5 pack.

Dom

Thanks for replying.

"...is installing a 5.6K ohn resistor inline with the air temp sensor."

Any pictures or diagrams as to where exactly and how to install?

Anyone else who has tried this happy with the results?

:rolleyes:

I have done this. However I used an 8k resistor and it works great!

Ok what is this resistor, what is it your doing? I have a Injen Technology Cold Air Intake. I get a bit of heat soak when the down pipe heats up. My only solution i see is to wrap the pipe with a insulant sleeve or something like thermo tec. to reduce heat.

Which wire (I think there are two on the IAT) did you splice the resister to. I am using the KKM with the origional location for the IAT, on the top with that little holder. I tried to relocate it to the side of the rubber flex pipe but I couldn't get a good seal between the rubber and the IAT and the car ran really poor.

Hmmm. some thoughts from someone living at 5300ft. I can't get enough air up here, and the last thing I need to do is richen up the mix. I've got more fuel than I know what to do with, which was confirmed when I was dynoing the car w/wide band O2 sensor in place.
I thought that running on the rich side of stoic. was going to lose HP compared to running lean. Lean means more HP and cleaner running as long as the air volume remains the same, up to a point, like when you run too hot and melt a piston or plug I though that our cars ran rich to begin with and the goal here was to lean out the mix for more of vitamin HP. Since this mod does not increase airflow any, how is more fuel going to help? Any physics guru's out there want to comment on this?
I don't doubt that the resistor makes a difference, in fact it's been well documented to work very well with the Zetec guys. In fact, some of them even made a switch to turn it "on" and "off" due to the fact that after a while the car would not run as well w/the resistor in place. They were using it more as a means to advance ignition timing, which will make more HP, as proven by the Superchip.
I think the KKM "heatsoak" problem is more to do with the fact that the KKM is able to breath in more HOT air than the stock, shielded intake can. We know that hot air is less dense than cool air. Less density = less O2 per given volume, which means less HP. With the restricted breathing our cars already have, a little increase in temp can have a dramatic effect on performance.
Also, to address your KKM concerns, it's not the KKM that leans the mix out, it's the fact that the KKM consistanly allows higher intake temps than the stock airbox that causes the lean condition. The higher the intake temp, the leaner the computer makes the mix (less air needs less fuel).
I'm NOT arguing the final result here, just the logic you use to arrive at it.

instead of a resister install a potentiometer (liniear volume control)to the iat and if you want to get aggresive install another one to the ect sensor when you turn them on your car thinks its trying to warm up and advances timing and richens the mixture for a greater edge had this on my 95se and although I never got any dyno or g-tech runs It made 14hp on a zx2 over on there site. go to fastcougar and do a search on "some free mods in the works" me and a few others did it and theres a digram you can use in the howtos.

the ect is hard to get to and solder thow.

Has someone verifyed this does not cause a lean condition or ping in a normal duratec? Just checking...

I did it in mine. No pinging, or lean condition to speak of. I believe the purple wire is the one you put it into (cant remember exactly) Check the Ohio forum there should be a topic in there about the resistor mod.

Cya
Mike